1. Field of the Invention
The present invention relates to a capping device for a print head in a printing apparatus, and more particularly, a capping device and a printer including it for preventing the destruction of the meniscus of the print head.
2. Related Art of the Invention
To prevent the drying of ink ejection nozzles of a print head, it has been customary practice to cap the print head with a capping device. During the capping, the temperature of the space closed by the print head and the capping device (hereinafter referred to as the cap space) may vary under the influence of changes in the ambient temperature. In this situation, the volume of the cap space increases or decreases, and the pressure of the cap space varies. The meniscus of the print head is destroyed under a very low pressure. Thus, the pressure of the cap space needs to be kept at a low pressure at which the meniscus is not destroyed. As a means for keeping the pressure of the cap space constant, there has been proposed a maintenance mechanism for a print head, the maintenance mechanism having a communication passage between the cap space and the ambient air, and a valve mechanism in the communication passage, and controlling the opening and closing of the valve mechanism in response to changes in the temperature of the cap space. U.S. Pat. No. 4,684,963 discloses an ink jet printer equipped with a damper chamber which communicates with a cap chamber via a tube and which has a flexible member for absorbing pressure fluctuations inside the cap chamber.
With the above maintenance mechanism for the print head, however, the part other than the capping device, i.e., the valve mechanism, must be mounted for maintenance purposes. This poses the problems of making the structure complicated and the apparatus large.